Patent GB-996188-A (GB)
Title: Photographic camera
IPC: G03B7/12
Filed: 1962-03-02
Abstract: 996,188. Photographic cameras. AGFA A.G. March 2,1962 [March 4,1961], No. 8277/62. Heading G2A. In a camera having an automatic exposure regulating device including a follow-up device for the galvanometer needle of a photo-electric exposure meter which becomes operative on actuation of a release member, the exposure value setting means comprising a shutter speed setting means coupled to the follow-up device and a return spring-loaded diaphragm setting means arranged to derive setting movement from the shutter setging means through a one-way coupling, manually operable means is provided for arresting the shutter speed setting means in its initial setting position and means is also provided for setting the diaphragm manually independently of the shutter speed setting means typically a manual mode-ofexposure changeover ring is interconnected with the speed setting ring so that when the changeover ring is in any position other than that for automatic exposure regulation, rotation of the speed setting ring by the automatic exposure regulating means is prevented. As shown, on depressing the camera release 22, a spring 16 pivots downwardly the movable jaw 13 of a galvanometer needle sensing device including a fixed jaw 20 and this movement of the jaw 13 is transmitted to a ring 5 as a clockwise rotation by the forked end of a lever 8 engaging a pin 6 on the ring. Drive is transmitted to the shutter speed setting ring 3 by a tension spring 27 between a lug 29 on the ring 5 and a pin on a projection 28 on the ring 3 which has cam slots 30, 31 engaging pins 32, 33 on the shutter retard mechanism and bulb lever respectively, slot 31 normally holding the bulb lever inoperative. With the changeover ring 35 in the automatic regulation position shown with the mark 36 against the fixed index 39 as shown, ring 3 is free to be rotated clockwise by the tension spring 27 and as a result of rotation of the ring 3 cam slot 30 increases the shutter speed setting. If the scene is sufficiently bright so that rotation of the rings 5, 3 is continued beyond the fastest speed setting, pin 32 runs along a portion of the slot 30 concentric about the axis of the ring and a projection 46 on the ring engages a pin 47 on the movable diaphragm blade supporting ring 4 so as to reduce the aperture. Finally after a travel sufficient to allow the jaw 13 to complete its maximum possible movement, a pin 25 on the release 22 trips the shutter trigger 26 and on freeing the release the parts are spring returned to the position shown. For flashlight exposures the ring 35 is set with the mark 37 against the index 39 when a projection 40 pivots a lever 42 to block the path of a pin 45 on the ring 3, and the diaphragm is set manually to the chosen value by a ring 54 having a nose 55 engaging a similar nose 56 on the ring 4. On operation of the release 22 lug 29 on ring 5 moves away clockwise from the projection 28 on the ring 3 which is held stationary so that the shutter is set for the slowest speed. For bulb exposures the ring 35 is moved further to bring mark 38 against index 39 and in so doing the lever 42 drives the shutter speed setting ring anticlockwise so that an enlarged portion 34 of the cam slot 31 comes opposite the bulb lever pin 33 while the pin 32 moves along a further concentric portion of the slot 30. In the return to automatic exposure operation from both flashlight and bulb exposure settings the changeover ring 35 allows the spring 48 to return the diaphragm to its maximum aperture, an arm 61 on the ring 35 engaging an arm 59 on the manually operable ring 54.